I have a customer in MA that has a 3200 sq. ft. house, many different angles, peaks, etc. He wants the roof cleaned of mold, lichen stains, moss, etc., but keep they grey weathered look. The roof is approx 20 yrs old, and says it is worst this year becasue of all the rain we had. Is there any way to keep they grey weathered look while cleaning the roof. Also, he wants the roof sealed/stained also. Bringing in a lift to do the job is also not a problem with the owner. Any ideas on pricing and what is best sealant for the job. Thanks